Strength Of Materials Finals

Front 1

Branch of mechanics that studies the internal effects of stress and strain in a solid body that is subjected to an external loading.

Back 1

Mechanics of Materials

Front 2

Deals with the relations between externally applied loads and their internal effects on the body

Back 2

Strength of materials

Front 3

Defined as the strength of a material per unit area or unit strength.

Back 3

Stress

Front 4

Former unit of stress

Back 4

psi (now in N/mm^2 or MPa)

Front 5

Either the tensile or compressive stress

Back 5

Normal Stress or Axial Stress

Front 6

__ will tend to shorten the member.

Back 6

Compression

Front 7

__ will tend to lengthen the member

Back 7

Tension

Front 8

Forces parallel to the area resisting the force cause __

Back 8

Shearing Stress or Tangential Stress

Front 9

Other types of shearing stress

Back 9

Punching shear

Single shear

Double shear

Front 10

Contact pressure between the separate bodies. It is the internal stress caused by compressive forces

Back 10

Bearing stress

Front 11

Also known as unit deformation. It is the ratio of the change in length caused by the applied force to the original length.

Describes the geometry of deformation, independent of what actually causes the deformation

Back 11

Simple Strain

Front 12

Characterizes dimensional changes

Back 12

Normal Strain

Front 13

Describes distortion (changes in angles)

Back 13

Shear Strain

Front 14

The testing machine that elongates the specimen at a slow, constant rate until the specimen ruptures.

Back 14

Tensile Test

Front 15

Stress-Strain Diagram

Back 15

0

--

Proportional Limit

Elastic Limit

Yield Point

--

Ultimate Strength -> Actual Rupture Strength

Rupture Strength

Front 16

Metallic engineering materials are classified as either __ or __ materials

Back 16

ductile - brittle

Front 17

One having relatively large tensile strengths up to the point of rupture like structural steel and aluminum

Back 17

Ductile

Front 18

Has a relatively small strain up to the point of rupture like cast iron and concrete

Back 18

Brittle

Front 19

Arbitrary strain of __ is frequently taken as the dividing line between brittle and ductile classes

Back 19

0.05 mm/mm

Front 20

Stress strain diagram is a straight line from the origin 0 to a point called the __. Beyond this point, stress is no longer proportional to strain.

Back 20

Proportional Limit

Front 21

The stress-strain diagram is a manifestation of __

Back 21

Hooke's Law

Front 22

The stress-strain proportionality is assumed to exist up to a stress at which the strain __ at a rate of __ greater than shown by the initial tangent to the stress-strain diagram

Back 22

increases - 50%

Front 23

This linear relation between elongation and the axial force causing was first noticed by __ in __ and is called __ that within the proportional limit, the stress is directly proportional to strain.

Back 23

Sir Robert Hooke - 1678 - Hooke's Law

Front 24

Constant of proportionality E is called the __, a measure of the stiffness of a material.

Back 24

Modulus of Elasticity or Young's Modulus

Front 25

The value of E is equal to __

Back 25

Slope of the straight line.

Front 26

The ratio of the steady force acting on an elastic body to the resulting displacement.

Back 26

Stiffness (k)

Front 27

__ is the stress beyond which the material is no longer elastic. It is the value of stress on the stress-strain curve at which the material has deformed plastically

Back 27

Elastic Limit

Front 28

The elastic limit is __ than the proportional limit

Back 28

slightly larger

Front 29

The permanent deformation that remains after the removal of the load is called ___

Back 29

Permanent set

Front 30

A material is said to be __ if , after being loaded, the material returns to its original size and shape when the load is removed

Back 30

Elastic

Front 31

The region in the stress-strain diagram from 0 to P.

Back 31

Elastic Range

Front 32

The region from P to R.

Back 32

Plastic Range.

Front 33

The point where the stress-strain diagram becomes almost horizontal is __ and its corresponding stress is __

Back 33

Yield Point - Yield Stress or Yield Strength

Front 34

The highest stress on the stress-strain diagram

Back 34

Ultimate strength

Front 35

The maximum ordinate in the stress-strain diagram.

Back 35

Actual rupture strength or

Tensile strength or

Ultimate strength

Front 36

The stress at which failure occurs

Back 36

Rupture strength or rupture stress

Front 37

The strength of the material at rupture.

Back 37

Breaking strength

Front 38

The Big Question:

The nominal rupture strength (for structural strength) is considerably lower than the actual rupture strength. Why?

Back 38

Because the nominal rupture strength is computed by dividing the load at rupture by the original cross-sectional area. The actual rupture strength is calculated using the reduced area of the cross section where the fracture occurred.

Front 39

The work done on a unit volume of material as the force is gradually increased from 0 to P

Back 39

Modulus of Resilience

Front 40

The __ of a material is its ability to absorb energy without creating a permanent distortion

Back 40

Resilience

Front 41

The work done on a unit volume of material as the force is gradually increased from 0 to R

Back 41

Modulus of Toughness

Front 42

The __ of a material is its ability to absorb energy without causing it to break

Back 42

Toughness

Front 43

Term describing the structural capacity of a system beyond expected or actual loads

Back 43

Factor of Safety

Front 44

The maximum axial stress used in design

Back 44

Working Stress or Allowable Stress

Front 45

Working stress should be limited to values __ so that the stresses remain in the __.

Back 45

not exceeding the proportional limit - elastic range

Front 46

Because the proportional limit is difficult to determine accurately, it is customary to base the working stress on either the yield stress or the ultimate stress divided by a suitable number called __

Back 46

Factor of Safety

Front 47

The Big Question (2):

Why is the yield stress easier to determine accurately than the proportional limit?

Back 47

For wider range of strain, yield stress does not vary significantly

Front 48

__ causes shearing deformation

Back 48

Shearing forces

Front 49

The change in angle at the corner of an original rectangular element is called __

Back 49

Shear strain

Front 50

The ratio of the shear stress and the shear strain is called __.

Back 50

Modulus of Elasticity or Modulus of Rigidity

Front 51

__ showed that the ratio of the transverse strain to the axial strain is constant for stresses within the proportional limit. This constant is called __.

Back 51

Simeon D. Poisson (1811) - Poisson's ratio

Front 52

Common values of Poisson's ratio are:

__ for steel

__ for other metals

__ for concrete

__ max

Back 52

Steel: 0.25 - 0.30

Others: 0.33

Concrete: 0.20

Max: 0.5

Front 53

The __ is uniform throughout the cross section and is the same in any direction in the plane of the cross section

Back 53

Transverse strain

Front 54

__ is the shear modulus of elasticity (simple shear modulus), or the modulus of rigidity. (Pa or psi)

Back 54

G

Front 55

Modulus of Elasticity (Young's Modulus) Formula

Back 55

E = Stress/Strain

Front 56

Modulus of Rigidity (Shear Modulus) Formula

Back 56

G = Shearing Stress/Shearing Strain

Front 57

Bulk Modulus Formula

Back 57

E = Volume Stress/Volume Strain

Front 58

Measure of a resistance of a material to change in volume without change in shape or form

Back 58

Bulk modulus of elasticity (K)

Front 59

If the equilibrium equations are sufficient to calculate all the forces (including support reactions) that act on a body, these forces are said to be __.

Back 59

Statically determinate

Front 60

The number of unknown forces is __ to the number of independent equilibrium equations.

Back 60

always equal to

Front 61

If the number of unknown forces exceeds the number of independent equilibrium equations, the problem is said to be __

Back 61

Statically indeterminate

Front 62

Mathematical expressions of geometric restrictions imposed on the deformation of statically indeterminate problems

Back 62

Compatibility Equations

Front 63

Internal stress created

Back 63

Thermal stress

Front 64

Pressurized container often cylindrical or spherical.

Back 64

Pressure vessel

Front 65

Resist bursting forces developed across longitudinal and transverse sections.

Back 65

Tensile forces

Front 66

The stress in the longitudinal section that resist the bursting force

Back 66

Tangential stress

Front 67

Tangential stress is also called

Back 67

Circumferential stress

Hoop stress

Girth stress

Front 68

Acts parallel to the longitudinal axis of the cylinder

Back 68

Longitudinal stress

Front 69

Twisting of an object due to applied torque

Back 69

Torsion

Front 70

Tendency of a force to rotate on an object about an axis (fulcrum or pivot); measure of resistance to twisting

Back 70

Torque

Front 71

Modulus of rigidity; ratio of shear stress to shear strain; concerned with the deformation of a solid when it experiences a force parallel to one of its surfaces

Back 71

Shear Modulus

Front 72

Quantity used to predict an object's ability to resist torsion

Back 72

Polar Moment or Inertia (J)